Perinatal Data Collection
NSW Ministry of Health
Background
The NSW Perinatal Data Collection (formerly known as the Midwives Data Collection) is a population-based surveillance system covering all births in NSW public and private hospitals, as well as homebirths. The data collection has operated since 1987 but only continuously since 1990. The Perinatal Data Collection (PDC) is a statutory data collection under the NSW Public Health Act 2010.
The PDC encompasses all live births, and stillbirths of at least 20 weeks gestation or at least
400 grams birth weight. For every birth in NSW the attending midwife or medical practitioner completes a form (or its electronic equivalent) giving demographic, medical and obstetric information on the mother, and information on the labour, delivery and condition of the infant. Completed forms are sent to the Data Integrity and Governance Unit, Information Management and Quality, in the Health System Information and Performance Reporting Branch of the NSW Ministry of Health, where they are compiled into the PDC database. Around two-thirds of PDC notifications are received electronically from hospital obstetric information systems. There are several electronic systems that generate the PDC data including ObstetriX and Cerner.
The information sent to the NSW Ministry of Health is checked and compiled into one statewide dataset. One record is reported for each baby, even in the case of a multiple birth. The PDC was revised in 1998, 2006 and 2011. The PDC includes notifications of births which occur in NSW which includes women whose usual place of residence is outside NSW and who give birth in NSW; it does not receive notifications of interstate births where the mother is resident in NSW. The collection is based on the date of birth of the baby.
Access to information on Aboriginal and Torres Strait Islander peoples
An application to the Aboriginal Health and Medical Research Council (AH&MRC) ethics committee should be made for research projects for which one or more of the following apply:
· The experience of Aboriginal people is an explicit focus of all or part of the research
· Data collection is explicitly directed at Aboriginal peoples
· Aboriginal peoples, as a group, are to be examined in the results
· The information has an impact on one or more Aboriginal communities
· Aboriginal health funds are a source of funding
Research that is not specifically directed at Aboriginal people or communities, such as for the total population or a sub-population (e.g. rural NSW, people over 50 years old) can still potentially impact on Aboriginal people.
However, an application for such research need only be made to the Committee if any one of the following applies:
· Any of the five factors listed above are present; or
· Aboriginal people are known, or are likely, to be significantly over-represented in the group being studied (e.g. compared to the 2.1% of the total NSW population as shown in the 2006 Census); or
· The Aboriginal experience of the medical condition being studied is known, or is likely, to be different from the overall population; or
· There are Aboriginal people who use the services being studied in distinctive ways, or who have distinctive barriers that limit their access to the services; or
· It is proposed to separately identify data relating to Aboriginal people in the results.
The AH&MRC ethics committee have some specific requirements, including evidence of community engagement in the research. Relevant documents can be found on the AH&MRC website at: http://www.ahmrc.org.au. If you are unsure whether an application to the AH&MRC Ethics Committee is required, please seek the advice of the Ethics Committee secretariat (T: 02 9212 4777).
Tips for using the PDC in linkage studies
· While the PDC has operated continuously since 1990, personal identifiers were only included in the data collection after 1992, when it became a statutory data collection under the NSW Public Health Act 1991. There was also a revision to the PDC form in 1993, which was implemented gradually. Consequently, personal identifiers and a number of other fields are available for approximately half of the 1993 records. For these reasons it is recommended that record linkage studies be carried out using data collected from 1994.
· The PDC record contains information on mothers and babies. As the CHeReL links records for the same person (rather than across generations), two sets of personal identifiers from the PDC records are provided to the CHeReL—one for mothers and one for babies. These are known as the PDC mother and PDC baby datasets. When using the PDC in linkage studies, please consider whether mothers or babies or both are of interest. If both mothers and babies are of interest, the CHeReL will create a PDC mother linkage key and a PDC baby linkage key. The data custodian will add both mother and baby project person numbers (PPNs) to the PDC dataset for provision to the project investigators.
2 / Perinatal Data Collection Last updated February 2014Data custodians
Tim Harrold
A/Principal Epidemiologist and Manager, Health Services
Biostatistics and Epidemiology
Centre for Epidemiology and Research
NSW Ministry of Health
Locked Bag 961
NORTH SYDNEY NSW 2059
Phone: 02 9424 9142
Fax: 02 9391 9232
E-mail:
2 / Perinatal Data Collection Last updated February 2014
Perinatal Data Collection – Variable information
Variable / Description/Notes / Codes /Mother’s date of birth / Full date of birth will only be supplied if sufficient justification is supplied that age is insufficient. Date of birth may otherwise be supplied as MMYYYY.
Mother’s age / Age in years
Mother’s country of birth / The country in which the mother was born / Codes are the Australian Bureau of Statistics 4 digit country of birth names
http://www.abs.gov.au/ausstats/abs@.nsf/mf/1269.0
Mother’s Aboriginality / Used for trends from 1994 to present. See notes above regarding access to this variable. / 1 = Aboriginal or TSI
2 = Non-Aboriginal
9 = Not stated
Mother’s Indigenous status / Mother’s Indigenous status. Used from 1998 onwards. See notes above regarding access to this variable. / 1 = Aboriginal
2 = Torres Strait Islander
3 = Aboriginal and Torres Strait Islander
4 = None of the above
9 = Not stated
Mother’s marital status / Available for 1994-1997 / 1 = Married (inc. de facto)
2 = Never married
3 = Divorced, separated or married
9 = Not stated
**OTHER** = Invalid data
Hospital of birth / Hospital of birth for live births and stillbirths. / Code lists are updated regularly. If information on specific facilities is required, these should be specified by name.
Health Area of hospital / Health Area of hospital. Not available from 2011 onwards / See Attachment 1 – Area Health Services
Local Health District of hospital / Local Health District of hospital / See Attachment 2 – Local Health Districts
Mother’s postcode / Mother’s postcode of residence
Mother’s SLA of residence / SLA of residence / Codes are according to the Australian Standard Geographical Classification (ASGC) issued by the Australian Bureau of Statistics http://www.abs.gov.au/ausstats/abs@.nsf/mf/1216.0
Health Area of residence / Health Area of residence (2006). Not available from 2011 onwards / See Attachment 1 – Area Health Services
Local Health District of residence / Local Health District of residence / See Attachment 2 – Local Health Districts
Hospital Insurance status / Available for 1994-1997 / 1 = Yes (Private)
2 = No (Public)
9 = Not stated
Baby’s date of birth / Full date of birth will only be supplied if sufficient justification is supplied that age is insufficient. Date of birth may otherwise be supplied as MMYYYY.
Date of LMP / Date of last menstrual period. Available for 1994-2006. Full date will only be supplied if sufficient justification is supplied that gestational age is insufficient.
EDC / Expected date of confinement. Available for 2006 onwards. Full date will only be supplied if sufficient justification is supplied that gestational age is insufficient.
Previous pregnancy >20 weeks gestation? / Previous pregnancy greater than 20 weeks gestation / 0 = No
1 = Yes
9 = Not stated
Number of previous pregnancies / Number of previous pregnancies greater than 20 weeks gestation
Was last birth by caesarean section? / Available from 1998 onwards / 0 = No
1 = Yes
9 = Not stated
Total number of previous caesarean section / Available from 1998 onwards
Amniocentesis (<20 weeks) / Available for 1994-1997 / 0 = No
1 = Yes
9 = Not stated
CVS (<20 weeks) / Chorionic villus sampling. Available for 1994-1997 / 0 = No
1 = Yes
9 = Not stated
Cervical suture / Available for 1994-1997 / 0 = No
1 = Yes
9 = Not stated
Antenatal care / Was antenatal care received? Available for 2006 onwards. / 0 = No
1 = Yes
9 = Not stated
Duration of pregnancy (weeks) at first antenatal visit / Duration of pregnancy at first antenatal visit, available from 1994-2010
Duration of pregnancy (weeks) at first antenatal visit / Duration of pregnancy at first comprehensive booking or assessment by clinician. Available from 2011 onwards
Number of antenatal visits / Available from 2011
Not booked / Available for 1994-1997 / 0 = No
1 = Yes
9 = Not stated
Smoking during pregnancy / Did the mother smoke at all during pregnancy? Available from 1994-2010 / 0 = No
1 = Yes
9 = Not stated
Smoking during first half of pregnancy / Did the mother smoke during the first half of pregnancy? Available from 2011. / 0 = No
1 = Yes
9 = Not stated
Cigarettes per day during the first half pregnancy / How many cigarettes each day on average were smoked in the first half of pregnancy. Available from 2011 / 0 = Did not smoke
1 = Less than 1 per day
2 = 1-10 per day
3 = More than 10 per day
4 = Unknown
9 = Not-stated
Number of cigarettes smoked on average per day during the first half of pregnancy / Recorded values where “Cigarettes per day during the first half pregnancy” (see above) takes the values 2 or 3.
Smoking during the second half of pregnancy / Did the mother smoke during the second half of pregnancy? Available from 2011. / 0 = No
1 = Yes
9 = Not stated
Cigarettes per day 2nd half pregnancy / How many cigarettes each day on average were smoked in the second half of pregnancy / 1 = None
2 = More than 10 per day
3 = 1-10 per day
4 = Unknown
8 = Did not smoke during pregnancy
9 = Not stated
Cigarettes per day during the second half pregnancy / How many cigarettes each day on average were smoked in the second half of pregnancy. Available from 2011 / 0 = Did not smoke
1 = Less than 1 per day
2 = 1-10 per day
3 = More than 10 per day
4 = Unknown
9 = Not-stated
Number of cigarettes smoked on average per day during the second half of pregnancy / Recorded values where “Cigarettes per day during the second half pregnancy” (see above) takes the values 2 or 3.
Maternal diabetes mellitus / Maternal diabetes mellitus—pre-existing diabetes / 0 = No/not stated
1 = Yes
Gestational diabetes / Gestational diabetes / 0 = No/not stated
1 = Yes
Chronic hypertension / Chronic maternal hypertension / 0 = No/not stated
1 = Yes
Pregnancy-induced hypertension / Pregnancy-induced hypertension or pre-eclampsia. Available for 1994-2006 / 0 = No/not stated
1 = Yes
Pregnancy-induced hypertension - proteinuric / Available from 2006-2010 / 0 = No/not stated
1 = Yes
Pregnancy-induced hypertension – non-proteinuric / Available from 2006-2010 / 0 = No/not stated
1 = Yes
Pre-eclampsia / Available from 2011 / 0 = No/not stated
1 = Yes
Gestational hypertension / Available from 2011 / 0 = No/not stated
1 = Yes
APH (cause unknown) / Available for 1994-1997 / 0 = No/not stated
1 = Yes
APH (due to placenta abruptio) / Available for 1994-1997 / 0 = No/not stated
1 = Yes
APH (due to placenta praevia) / Available for 1994-1997 / 0 = No/not stated
1 = Yes
Blood group iso-immunisation / Available for 1994-1997 / 0 = No/not stated
1 = Yes
Prelabour rupture of membranes (>24 hours) / Available for 1994-1997 / 0 = No/not stated
1 = Yes
Threatened premature labor / Available for 1994-1997 / 0 = No/not stated
1 = Yes
Maternal Hepatitis B / Mothers who are hepatitis B surface antigen positive. Available for 1994-1997 and from 2011 onwards / 0 = No/not stated
1 = Yes
Major puerperal infection / Available for 1994-1997 / 0 = No/not stated
1 = Yes
Third degree tear / Available for 1994-1997 / 0 = No/not stated
1 = Yes
Shoulder dystocia / Available for 1994-1997 / 0 = No/not stated
1 = Yes
Retained placenta / Available for 1994-1997 / 0 = No/not stated
1 = Yes
Post-partum haemorrhage (>600mls) / Available for 1994-1997 / 0 = No/not stated
1 = Yes
Post-partum haemorrhage requiring blood transfusion / Available from 2006 / 0 = No/not stated
1 = Yes
Labour onset / Onset of labour / 1 = Spontaneous
2 = Induced
3 = No labour
9 = Not stated
Induction and augmentation of labour / Induction and augmentation of labour / 1 = Spontaneous
2 = Spontaneous augmented with ARM
3 = Spontaneous augmented with oxytocics/PGs
4 = No labour
5 = Induced - oxytocics/PGs